looking for 3-5W axial resistors rated for greater than 750V

M

Mook Johnson

Guest
I need some 49.9K - 51k resistors that will see peaks of 500V across them
for a few seconds.

I'm looking for some resistors that are reasonable in size that are rated
for greater than 750V that is readily avaialble.

Something like a MS220 form Caddock would work but it needs to be readily
available. Last itme I used these on a project they had a 6 week lead.
 
On Sun, 6 Apr 2008 20:36:38 -0500, "Mook Johnson" <mook@mook.net>
wrote:

I need some 49.9K - 51k resistors that will see peaks of 500V across them
for a few seconds.

I'm looking for some resistors that are reasonable in size that are rated
for greater than 750V that is readily avaialble.

Something like a MS220 form Caddock would work but it needs to be readily
available. Last itme I used these on a project they had a 6 week lead.

Pnasonic ERG 3W parts from digikey, although rated for 350V
continuous, accept 2.5xrated power to 700V and 4xrated power to 1KV.
As your peak stress is less than 2x rated, I don't see the issue with
specified voltage.

You can get lower-powered parts above 100K with book voltage ratings
of 1600V from digikey (vishay/BC Phoenix HVR). HVR68 has a 1W rating
(PPC1J100KCT-ND). It would mean using a few of them in parallel -
rather the opposite of what you seem to be trying to avoid (ie
resistors in series).

http://tinyurl.com/6k6rv6

These are similar to the series that would be used in safety-critical
bleeder circuits to ground in 250VAC systems.

RL
 
On Sun, 6 Apr 2008 20:36:38 -0500, "Mook Johnson" <mook@mook.net>
wrote:

I need some 49.9K - 51k resistors that will see peaks of 500V across them
for a few seconds.

I'm looking for some resistors that are reasonable in size that are rated
for greater than 750V that is readily avaialble.

Something like a MS220 form Caddock would work but it needs to be readily
available. Last itme I used these on a project they had a 6 week lead.

Pnasonic ERG 3W parts from digikey, although rated for 350V
continuous, accept 2.5xrated power to 700V and 4xrated power to 1KV.
As your peak stress is less than 2x rated, I don't see the issue with
specified voltage.

You can get lower-powered parts above 100K with book voltage ratings
of 1600V from digikey (vishay/BC Phoenix HVR). HVR68 has a 1W rating
(PPC1J100KCT-ND). It would mean using a few of them in parallel -
rather the opposite of what you seem to be trying to avoid (ie
resistors in series).

http://tinyurl.com/6k6rv6

These are similar to the series that would be used in safety-critical
bleeder circuits to ground in 250VAC systems.

RL
 

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